Honing oil, soft and hard oilstone all in one handy kit. A drop of oil (3 oz plastic bottle) on the soft Arkansas oilstone (4"L) helps the blade glide smoothly and turns a dull knife into a sharp one. Use the hard oilstone (3"L) for a final honing and an extra fine edge. A drop or two of oil keeps carbon blades from rusting and the pins lubricated.